Ellipse circle drawing instrument



p 30, 1969 I H. IRAVANI 3,469,319

ELLIPSE CIRCLE DRAWING INSTRUMENT Filed May 7, 1968 United States Patent3,469,319 ELLIPSE CIRCLE DRAWING INSTRUMENT Hooshang Iravani, Detroit,Mich. (P.O. Box 652, East Lansing, Mich. 48823) Filed May 7, 1968, Ser-No. 727,149 Int. Cl. B431 11/04 US. Cl. 33-30 3 Claims ABSTRACT OF THEDISCLOSURE An ellipsoidal compass for selectively drawing either circlesor ellipses of varied shapes and sizes, the device comprising a pair ofspaced legs extending at an angle respective to each other, the legsbeing retained to rotate within a circular ring which when beingretained in a plane parallel to the drawing surface will cause thecompass to draw a circle, but wherein if the ring is inclined at anangle respective to the drawing surface will cause the compass to drawan ellipse, the particular shape of the ellipse being defined by theamount of inclination of the ring.

This invention relates generally to ellipsographs.

A principal object of the present invention is to provide an ellipsoidalcompass which may be used selectively for drawing either circles orellipses.

Another object of the present invention is to provide an ellipsoidalcompass which can draw circles of various sizes and ellipses of varioussizes.

Yet another object of the present invention is to provide an ellipsoidalcompass wherein the ellipses may be made of different relative width tothe length thereof which is generally defined as ellipses of aparticular angle.

Other objects of the present invention are to provide an ellipsoidalcompass which is simple in design, inexpensive to manufacture, rugged inconstruction, easy to use and eflicient in operation.

These and other objects will be readily evident upon a study of thefollowing specification and the accompanying drawing wherein:

FIG. 1 is a perspective view of the present invention shown in operativeuse;

FIG. 2 is a perspective view of one of the compass legs of the presentdevice;

FIG. 3 is a perspective view of the other of the compass legs;

FIG. 4 is a perspective view of one of the components of the presentinvention comprising an outer ring;

FIG. 5 is a perspective view of another component comprising an innerring; and

FIG. 6 is a view of the guide post.

Referring now to the drawing in detail, the reference numeral 10represents an ellipse-circle drawing instrument according to the presentinvention wherein there is a compass unit 11 comprised of a long leg 12and a short leg 13, the legs being pivotable at their one ends about abearing 14, the ends being maintained in frictional engagement with thebearing by means of a spring 15, as shown in FIG. 1 of the drawing. Thebearing 14 includes a pin at one end of a shaft 16 which extends throughan opening in the spring 15, the end of the shaft having a handle 17generally used for swinging the compass.

The opposite end of the leg 13 is provided with a pivotable bearing 18which is mounted to pivot about a pin 19 extending transversely throughthe leg 13.

The other leg 12 is provided at its opposite end with an opening intowhich a shaft 20 is press fitted, the shaft 20 having a slidable stylus21 carried thereupon. The stylus may either support a pencil lead 22 forpurpose of writing upon a drawing surface 23, or it may carry an inkstylus as preferred. The stylus may be secured in a selective posi-Patented Sept. 30, 1969 tion upon the shaft 20 when used to draw anellipse or a circle of a selected size. Along an intermediate portion ofthe leg 12 there is an elongated slot 23 as shown in FIG. 2 of thedrawing.

An inner ring 25, shown in FIG. 5 includes a circular rim 26 having adiametrically extending bar 27 thereacross, the bar being integraltherewith. The bar 27 is fitted through an opening 28 within the bearing18 of the compass leg 13, and the bar 27 is additionally fitted throughthe slot 23 of the other leg 12.

The ring 25 is fitted within a groove of circular configuration within acircular outer ring 29. Thus the outer ring 29 comprises a member thathas a hollow, circular recess upon its inner periphery into which theinner ring 25 is fitted and wherein the inner ring is slidable. Theouter ring 29 is provided with a pair of outwardly extending shaft stubs30 located diametrically apart, as shown in FIG. 4. The stub shafts 30are supported pivotally free within bearings 31 of a V-frame 32 whichmay be fitted around an upstanding guide post 33. The lower end of theguide post is provided with a needle 34 of relatively short length so asto anchor the same within the surface of the drawing paper.

When it is desired to employ the present device for drawing a circle,the guide post is first set up so as to maintain the instrument in a setlocation upon the drawing. The stylus 21 is moved along the shaft 20 toa desired position so to get a proper size of circle to be drawn. Theouter ring 29 is maintained in a horizontal position relative to thedrawing surface, and the compass until 11 is then rotated by means ofthe handle 17. The stylus will thus draw a true circle. In order to drawan ellipse, the outer ring 29 is tilted respective to the drawingsurface so that as the leg 12 rotates, it will move through a relativelylong axis which extends across the bearings 31 and which is defined withthe reference numeral 35. At this position, the long dimension of anellipse is drawn. When the compass unit is rotated degrees thereto, theleg will be on a line which comprises a minimum axis due to the tiltedouter ring in the bearings 31. Depending on the amount of tilt of thering, the particular shape of the ellipse will be described. Thus if thering is tilted to a maximum, the ellipse will have a relatively longaxis but a very short axis perpendicular thereto.

It is to be understood that this invention may be modified by employinginner and outer rings which are of ellipsoidal configuration instead ofas shown to comprise true circles. Thus an additional assortment ofellipses may be described.

Thus there has been provided an ellipsograph which may draw circles orellipses of various sizes and of various shapes.

While various changes may be made in the detailed construction, it isunderstood that such changes will be within the spirit and scope of thepresent invention as is defined by the appended claims.

I claim:

1. In a circle ellipse drawing instrument, the combination of a compassunit, said compass unit comprising a pair of diverging legs, one end ofsaid legs being pivotable about a bearing, the opposite end of said legsbeing selectively adjustable apart, and means for confining the distanceapart of the other ends of said legs, said means having characteristicsfor selectively having said compass unit describe a circle or anellipse, one of said compass legs comprising a short leg and the otherof said compass legs comprising a long leg, said short leg having at itsopposite end a freely pivotable bearing pivotable about a pin mountedtransversely through said leg, said bearing having a central openingtherethrough, the other of said compass legs comprising said long legbeing provided with a sidewa'rdly extending shaft affixed thereto, saidshaft supporting a slideable stylus thereupon, said stylus carrying ameans for drawing upon a drawing surface, an intermediate portion ofsaid long leg having alongitudinally extending slot therethrough, saidmeans comprising an inner ring and an outer ring, said inner ringcomprising a circular rim having a diametrically extending bar integraltherewith, said bar being received through said slot of said long legand said opening of said bearing in said short leg.

2. The combination as set forth in claim 1 wherein said outer ring has acircular groove on the inner periphery thereof to receive said innerring pivotally free there within.

outer ring includes a pair of radially outwardly extending stub shaftsretained pivotally free between diverging legs of a V-frame selectivelysupportable about an upstanding guide post.

References Cited UNITED STATES PATENTS 828,372 8/ 1906 Becker. 2,690,0139/ 1954 MacGuirc. 3,137,945 6/ 1964 Da Silva.

FOREIGN PATENTS 597,111 8/ 1925 France.

3. The combination as set forth in claim 2 wherein said 15 HARRY N.HAROIAN, Primary Examiner

